Third-party testing laboratory instruments have requirements for samples submitted for inspection

Source: Date: 2021-8-20

1. Nuclear magnetic resonance spectrometer:

(1) The purity of the sample submitted for inspection should generally be >95%, free of iron filings, dust, filter paper lint and other impurities. Generally, the amount of sample required for organic matter: 1H spectrum>5mg, 13C spectrum>15mg, the amount of sample required for polymers should be increased appropriately.

(2) The configuration of this instrument can only perform liquid sample analysis. The sample is required to have good solubility in a certain deuterated solvent. The sample sender should first choose the solvent to be used. The deuterated solvents in this room are chloroform, heavy water, methanol, acetone, DMSO, benzene, o-dichlorobenzene, acetonitrile, pyridine, acetic acid, and trifluoroacetic acid.

(3) The sender is requested to provide the possible structure or source of the sample as much as possible. If you have special requirements (such as detection temperature, spectral width, etc.), please explain.


2. Infrared spectrometer:

In order to protect the instrument and ensure the quality of the infrared spectrum of the sample, the sample sent to the instrument for analysis must be:

(1) The sample must be purified in advance to ensure sufficient purity;

(2) The sample must be dewatered and dried in advance to avoid damage to the instrument and at the same time to avoid the interference of water peaks on the sample spectrum;

(3) For samples that are prone to deliquescent, please prepare your own desiccator for storage;

(4) For samples that are volatile, sublimable, and unstable to heat, please use a container with a sealed lid or stopper to hold and close tightly. At the same time, it must be noted on the sample analysis task sheet;

(5) For toxic and corrosive samples, users must pack them in sealed containers. The samples must be clearly marked on the label of the sample bottle and on the analysis task sheet when sending samples.


3. Organic mass spectrometer:

Suitable for analyzing liquid and solid organic compound samples with a relative molecular mass of 50 ~ 2000u. The sample should be as pure as a single component.


4. Gas Chromatography-Mass Spectrometer:

All gas chromatographs use capillary columns (packed columns cannot be used).

The sample entering the gas chromatography furnace must be completely vaporized within the working temperature range of the chromatographic column.


5. Liquid chromatography-mass spectrometer:

(1) Flammable, explosive, toxic, and corrosive samples must be noted.

(2) In order to ensure the accuracy and reliability of the analysis results, the sample is required to be completely dissolved without mechanical impurities; the sample that has not been prepared into a solution, please indicate the solvent, and the sample that has been prepared into a solution, please indicate the concentration.

(3) Please provide as much as possible the structural formula, molecular weight, or functional groups contained in the sample in order to select the ionization method; if you have special requirements, please provide specific experimental conditions.

(4) Liquid chromatography – When combined with mass spectrometry, all buffer systems are made of easily volatile buffers, such as acetic acid, ammonium acetate, and tetrabutylammonium hydroxide. Those who require quantitative analysis, please provide standard reference materials.


6. Time-of-flight mass spectrometer:

(1) Specimen type, composition and sample volume

This instrument is good at measuring peptides and proteins, as well as other biological macromolecules such as polysaccharides, nucleic acids and high molecular polymers, synthetic oligomers, and some organic substances with relatively small molecular weights, such as C60 or C60 grafts Etc. The test sample can be a single component or a multi-component, but the more the sample components, the more complex the spectrum and the more difficult the spectrum analysis; if there is mutual inhibition between the components during the ionization process , It is not necessarily guaranteed that each component has peaks. The sample volume for routine determination is about 1-10 picomoles/microliter.

(2) Solubility of the sample

The sample to be tested must be soluble in a suitable solvent, preferably an undissolved solid or pure liquid. If the sample is a solution, information about the solvent, concentration, or content of the sample should be provided.

(3) Purity

In order to obtain high-quality mass spectra, peptide and protein samples should avoid sodium chloride, calcium chloride, potassium hydrogen phosphate, trinitrotoluene, dimethyl sulfoxide, urea, glycerol, tween, dodecane Sodium sulfate and so on. If the test sample cannot avoid the use of the above reagents in the pretreatment process, the sample must be purified by dialysis and high performance liquid chromatography. Water, ammonium bicarbonate, ammonium acetate, ammonium formate, acetonitrile, trifluoroacetic acid, etc. are all suitable reagents for purifying samples. After the protein sample is purified, it should be lyophilized as much as possible. The salt in the sample can be removed by ion exchange.


7. Ultraviolet-visible absorption spectrometer:

(1) The concentration of the sample solution must be appropriate, and it must be clear and transparent, without bubbles or suspended substances;

(2) Solid sample size > 0.2g, liquid sample size > 2 ml.


8. Gas chromatograph:

The samples that can be directly analyzed should be volatile and thermally stable. The boiling point is generally not more than 300 ℃. If the sample cannot be directly injected, pre-treatment is required.


9. Liquid chromatograph:

The sample should be dry, and it is best to provide the structure of the component to be tested; for complex samples, provide as much as possible what other components may be in the sample.


10. Elemental analyzer:

(1) Fill in the element analysis sample registration form, and provide molecular formula and element theoretical content or other relevant information as much as possible;

(2) The sample must be a uniform solid particle or liquid that does not contain adsorbed water and has been purified. If the sample is not pure (contains adsorbed water, organic solvent, inorganic salt or other impurities), it will affect the analysis result and make the test value and the calculated value inconsistent;

(3) The sample should have sufficient amount to meet the linearity and sensitivity of the method and instrument.


11. Ion Chromatograph:

The sample submitted for inspection can be dissolved in water, or dilute acid or alkali, and the acid or alkali used must not contain the ion to be tested. For compounds that contain the element to be tested, but exist in a non-ionic state in water, acid, and alkali solutions, corresponding sample pretreatment is required.


12. Plasma atomic emission spectrometer:

(1) Requirements for samples submitted for inspection (test conditions):

①Please inform the sample source, type, attributes (such as ore, alloy, silicate, special solid solution, polymer, etc.).

List as far as possible the main components, impurity components and their (estimated) content; what is the minimum (estimated) content of the elements to be tested? For the solution, please specify the medium components (solvent, acid and alkali types and their (estimated) ) Content), fluorine (F-) or not? Because fluorine (F-) will seriously corrode the atomizer!

②The solid sample should be made into a solution without any organic matter, and its final acidity should be controlled to 1 mol, and the sample size: 5-50 ml.

If it contains suspended solids or precipitates, be sure to filter; please also send a reagent blank solution to deduct the blank at the same time, there is no charge for this item!

③The sample must be processed into a solution before being sent to the testing center.

(2) Due to conditions, the laboratory cannot analyze the following elements and certain substances:

①Volatile loss when the sample is heated and dissolved in acid (such as B, Hg, S-2, Se and Si when the sample is dissolved with hydrofluoric acid (HF));

②Ceramics, glass and other materials cannot be dissolved by inorganic acid and can only be melted by alkali;

③Organic silicon, silicon rubber, plastic products, fibers, or any ashing within 500 oC and subsequent acid digestion:

A. Volatile loss;

B. Those that cannot be ashed or cannot be dissolved (such as B, Bi, Ge, Hg, Os, Ru, Sb, Se, Sn, Tl and Si when the sample is dissolved with hydrofluoric acid (HF); special solid solution Body, polymer, etc.)


13. Atomic Fluorescence Spectrometer:

(1) General requirements for sample analysis

The object of atomic fluorescence spectrometer analysis is arsenic (As), selenium (Se), germanium (Ge), tellurium (Te), etc. and mercury (Hg) atoms that exist in ionic state. The sample must be aqueous or soluble Sour.

(2) Solid samples

①Inorganic solid sample The sample maintains proper acidity after simple dissolution.

Detect arsenic (As), selenium (Se), tellurium (Te), mercury (Hg), the medium is hydrochloric acid (5%, v/v);

Detect germanium (Ge), the medium is sulfuric acid (5%, v/v);

Detecting mercury (Hg), the medium can also be nitric acid (5%, v/v), and the detection (As) medium can also be sulfuric acid (2%, v/v).

Because copper, silver, gold, platinum and other metals have greater interference with the elements to be measured, the arsenic, selenium, tellurium, and mercury in these types of alloy samples should not be determined by this instrument.

②Organic or biological solid samples

The sample is nitrated into a solution and maintains proper acidity. The acidity of the medium is the same as that of the inorganic sample.

(3) Limit requirements for the elements to be tested in samples

Determined by the sensitivity of the instrument and the analysis method, the upper and lower limit of the element to be measured in the sample is 0.05 μg/g ~ 500 μg/g, and the test result of this instrument will not be guaranteed if the sample is not within this content range. Accurate and reliable.

(4) Sample size

For each element to be tested, the amount of solid sample is not less than 2 g, the amount of liquid sample is not less than 20 mL, and the amount of water sample is not less than 100 mL.

(5) Others

Please refer to relevant literature and materials before sending samples, and provide relevant information as much as possible.


14. Differential scanning calorimeter:

Solid samples will not decompose or sublime within the tested temperature range, and no volatile matter will be produced. Sample size: no less than 20mg for inorganic or organic materials and no less than 5mg for drugs in a single test. When sending samples, please indicate the detection conditions (including detection temperature range, temperature rise and fall rate, constant temperature time, etc.).


15. Thermogravimetric analyzer:

Sample volume: not less than 30mg. When sending samples, please indicate the detection temperature range, experimental atmosphere (air, N2 or Ar), heating rate, gas flow rate (if there are special requirements).


16. X-ray powder diffractometer:

The samples submitted for inspection can be powder, block, film and other shapes. The powder sample requires about 0.2g (depending on its density and diffraction ability); the bulk sample requires an approximate plane with an area less than 45px x 45px; the thin film sample requires a certain thickness with an area less than 45px x 45px; other samples are available Consult the laboratory.


17. X-ray single crystal powder diffractometer:

The sample submitted for inspection must be single crystal. When choosing a crystal, you should pay attention to the surface of the selected crystal is smooth and clean, the color and transparency are consistent. No small crystals are attached, and there are no defects such as overlapping defects, cleavage damage, and cracks. The length, width, and height of the crystal are all 0.1 ~ 0.4 mm, that is, the diagonal length of the crystal does not exceed 0.5 mm (large crystals can be sampled by cutting methods, and small crystals should consider their diffraction ability).


18. Transmission electron microscope:

Due to the high voltage limitation of the electron microscope, the transmitted electron beam generally can only penetrate thin samples with a thickness of several tens of nanometers or less. Except for fine granular samples that can be directly dropped by the medium dispersion method, other sample preparation methods mainly include physical thinning (ion and double spray thinning, etc.) and ultra-thin sectioning. Under normal circumstances, the sample preparation process that requires physical thinning method must be completed by the user (the department that does not have this sample preparation condition can rent the relevant equipment in this room). The preparation of ultra-thin section samples requires complicated procedures such as sample pre-processing, embedding, and slicing, and the cycle is relatively long (about one week).

Because the instrument is a high-resolution electron microscope, in order to ensure the performance of the instrument and give full play to its high-resolution image observation characteristics, it currently mainly accepts samples in the field of materials.


19. Field emission scanning electron microscope:

The samples submitted for inspection must be dry solid, block, flake, fiber or powder. It should have a certain degree of chemical and physical stability, and will not volatilize or deform under vacuum and electron beam bombardment; it is non-magnetic, radioactive and corrosive. For sample preparation of biological soft tissues with high water content, users are required to perform the fixation, cleaning, dehydration and replacement with (iso)amyl acetate before critical point drying, and finally the critical point drying treatment in this room. The sample for observing the image should be sprayed with gold film in advance. In general, the sample should be as small as possible (≤10x10x5mm is more convenient). Each powder sample needs about 1 gram. Nano samples generally need to be ultrasonically dispersed and sprayed with an ultra-fine gold film.


20. Scanning electron microscope-X-ray energy spectrometer:

The samples submitted for inspection must be dry solids, lumps, flakes, fibers, granules or powder. It should have a certain degree of chemical and physical stability, and will not volatilize or deform under vacuum and electron beam bombardment; it is non-magnetic, radioactive and corrosive. For biological soft tissue samples with high water content, users are required to perform fixation, cleaning, dehydration, and replacement with (iso)amyl acetate before critical point drying. Finally, the critical point drying treatment is carried out in this chamber. The image observation sample should be pre-plated with gold film, and the component analysis sample must be coated with carbon film. Under normal circumstances, the sample volume should not be too large (≤5x5x2mm is more suitable).